2030762 - Perma TEST-UNEXPECTED-FAIL | browser/base/content/test/static/browser_parsable_css.js | checkAllTheCSS - Got error message for resource://builtin-addons/webcompat/injections/css/bug2029246 | when Gecko 151 switches to beta on 2026-05-01

Status: VERIFIED FIXED

(Web Compatibility :: Interventions, defect)

Description

[Silaghi Andreea]

Central-as-beta-simulation

How to run these simulations

Failure log

[task 2026-04-09T13:52:18.036+00:00] 13:52:18     INFO - TEST-UNEXPECTED-FAIL | browser/base/content/test/static/browser_parsable_css.js | checkAllTheCSS - Got error message for resource://builtin-addons/webcompat/injections/css/bug2029246-discord.com-scrollbar-fix.css: Unknown pseudo-class or pseudo-element ‘-webkit-scrollbar’.  Ruleset ignored due to bad selector.
[task 2026-04-09T13:52:18.036+00:00] 13:52:18     INFO - chrome://mochikit/content/browser-test.js:test_ok:1885
[task 2026-04-09T13:52:18.036+00:00] 13:52:18     INFO - chrome://mochitests/content/browser/browser/base/content/test/static/browser_parsable_css.js:messageIsCSSError:332
[task 2026-04-09T13:52:18.036+00:00] 13:52:18     INFO - chrome://mochitests/content/browser/browser/base/content/test/static/browser_parsable_css.js:checkAllTheCSS:668
[task 2026-04-09T13:52:18.036+00:00] 13:52:18     INFO - chrome://mochikit/content/browser-test.js:handleTask:1376
[task 2026-04-09T13:52:18.036+00:00] 13:52:18     INFO - chrome://mochikit/content/browser-test.js:_runTaskBasedTest:1466
[task 2026-04-09T13:52:18.036+00:00] 13:52:18     INFO - chrome://mochikit/content/browser-test.js:Tester_execTest:1617
[task 2026-04-09T13:52:18.036+00:00] 13:52:18     INFO - chrome://mochikit/content/browser-test.js:nextTest/<:1356
[task 2026-04-09T13:52:18.036+00:00] 13:52:18     INFO - chrome://mochikit/content/tests/SimpleTest/SimpleTest.js:SimpleTest.waitForFocus/<:1060
[task 2026-04-09T13:52:18.037+00:00] 13:52:18     INFO - Not taking screenshot here: see the one that was previously logged
[task 2026-04-09T13:52:18.038+00:00] 13:52:18     INFO - TEST-UNEXPECTED-FAIL | browser/base/content/test/static/browser_parsable_css.js | checkAllTheCSS - All the styles (492) loaded without errors. - Got 1, expected +0
[task 2026-04-09T13:52:18.038+00:00] 13:52:18     INFO - chrome://mochikit/content/browser-test.js:test_is:1913
[task 2026-04-09T13:52:18.038+00:00] 13:52:18     INFO - chrome://mochitests/content/browser/browser/base/content/test/static/browser_parsable_css.js:checkAllTheCSS:669
[task 2026-04-09T13:52:18.038+00:00] 13:52:18     INFO - chrome://mochikit/content/browser-test.js:handleTask:1376
[task 2026-04-09T13:52:18.038+00:00] 13:52:18     INFO - chrome://mochikit/content/browser-test.js:_runTaskBasedTest:1466
[task 2026-04-09T13:52:18.038+00:00] 13:52:18     INFO - chrome://mochikit/content/browser-test.js:Tester_execTest:1617
[task 2026-04-09T13:52:18.038+00:00] 13:52:18     INFO - chrome://mochikit/content/browser-test.js:nextTest/<:1356
[task 2026-04-09T13:52:18.038+00:00] 13:52:18     INFO - chrome://mochikit/content/tests/SimpleTest/SimpleTest.js:SimpleTest.waitForFocus/<:1060
[task 2026-04-09T13:52:18.039+00:00] 13:52:18     INFO - Leaving test checkAllTheCSS
[task 2026-04-09T13:52:18.039+00:00] 13:52:18     INFO - GECKO(3447) | MEMORY STAT | vsize 11947MB | residentFast 772MB | heapAllocated 406MB
[task 2026-04-09T13:52:18.040+00:00] 13:52:18     INFO - checking for open sidebars
[task 2026-04-09T13:52:18.040+00:00] 13:52:18     INFO - checking window state
[task 2026-04-09T13:52:18.041+00:00] 13:52:18     INFO - Not taking screenshot here: see the one that was previously logged
[task 2026-04-09T13:52:18.041+00:00] 13:52:18     INFO - TEST-UNEXPECTED-FAIL | browser/base/content/test/static/browser_parsable_css.js | finished in 1820ms
[task 2026-04-09T13:52:18.041+00:00] 13:52:18     INFO - TEST-INFO took 1825ms
[task 2026-04-09T13:52:18.042+00:00] 13:52:18     INFO - TEST-START | browser/base/content/test/static/browser_parsable_script.js

Comment 1

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 2030762 - have browser_parsable_css.js ignore our webcompat CSS interventions using -webkit-scrollbar when layout.css.fake-webkit-scrollbar.enabled is false; r?dholbert

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/c06bd5af52f8
https://hg.mozilla.org/integration/autoland/rev/7803f4a39435
have browser_parsable_css.js ignore our webcompat CSS interventions using -webkit-scrollbar when layout.css.fake-webkit-scrollbar.enabled is false; r=dholbert

Comment 3

[rperta]

https://hg.mozilla.org/mozilla-central/rev/7803f4a39435

Comment 4

[Intermittent Failures Robot]

6 failures were associated with this bug in the last 7 days.

Repository breakdown:

• try: 6

Table

	no_variant	swr
linux2404-x86_64/opt		4
windows11-x86_64/opt	2

For more details, see:

https://treeherder.mozilla.org/intermittent-failures/bugdetails?bug=2030762&startday=2026-04-08&endday=2026-04-14&tree=all

Comment 5

[amarc]

verified fixed in today's central as beta simulation